As the Doctor Who 50th anniversary celebration illustrates, to be a Doctor Who fan is to learn to deal with highs and lows, often all at once.

For instance, along with the astronomical joy involved in an occasion like the show’s 50th anniversary episode — an extended, 75-minute love fest titled “The Day of the Doctor,” which will air in a global simulcast at 2:50pm Saturday, Nov. 23, on BBC America — comes the throat-tightening knowledge that Matt Smith’s four-year tenure in the role is ending. His final appearance will be in the very next episode, this year’s Christmas special.

Why now, Matt?

“It has come to a sort of a natural tipping point, and it’s at the top of a cycle, and I think … it’s a good time for me and for the show,” Smith told journalists this summer. “But I’ve had a great time. I’ll miss it, and it was a hard choice.”

The 11th Doctor isn’t going out alone, however. His predecessor, the also-beloved David Tennant (Broadchurch), will be on hand, along with Billie Piper (Secret Diary of a Call Girl) as companion Rose Tyler. In another exciting development, veteran actor John Hurt will appear as another mysterious version of the character, with some speculating he is “the Dark Doctor.”

Seeing as how the producers just love keeping things a secret — the plot of the episode, for instance — there surely will be a bounty of wonderful surprises for Whovians everywhere.

But even if you have no idea what a Time Lord is, or wonder why the heck everyone is so worried about a blue phone booth that’s called a TARDIS for some reason, producer Marcus Wilson says you can still have a good time with “The Day of the Doctor.”

“The show is largely made by fans of the show, so there’s stuff we want to bring back,” Wilson says. “But we always look at it in terms of we don’t want anybody to have to look at the show and know the history. You want to create characters and monsters that the new viewer will pick up.”

In that vein, Smith had encouraging words for fans who will be sad to see him go, even though there is great excitement for Peter Capaldi to take over the role.

“The thing about Doctor Who is that it always looks forward,” he says. “That’s the key. And the show will get bigger and better and carry on without me, and people will forget [pretending to cry].”